Electrical switch



July 26, 1927; 1,636,882

G. B. wADswoRTH ELECTRICAL SWITCH Fiied Jan. s. 1920 2 mets-snee: 1 /f1,3 1 F :,--1 ,"r-g ff @im @ne llil Patented July 26, 1927.

UNITE!) STATES GEORGE B. WADSWORTH, OF COVINGTON, ENTUCKY.

ELECTRICAL SWITCH.

Application led January 5, 1920.

My invention relates lo electrical switches of the type having a doublethrow. same being more particularly employed for the starting ofelectric motors 'in order to throw in progressively different windingsor ree sistances. thereby preventing the burning out of the motor by anexcessive Starting current.

In electric motor switches, there are various types of windings to whichmy invention would be applicable, but it is specially adapted in some ofits features to use with the star delta wound motors. The star deltawinding, which it is not neces` sary to describe in detail, has two setsot windings, uses a. three-wire delivery of current, and straps acrossthe threev wires so as to neutralize the central wire in startingposition. y

In the` past, the greatditliculty inY connection with the star deltawinding has been that the switches have not'been sutlicient to take careof the various connectionsv in a safe and foolproof manner. Thus therehave been in the past two switches for the star delta, one a main linevswitch and the other a double throw switch which either strapped thethree Wires of the system together, or directed a current. through ashunt for the additional motor winding. If the double-throw switch wereleft'in neutral position and the main linevswitchon, the motor wouldstop, but any short circuit would then burn out the motor, alsothe'throwing of the main switch would burn out the motor unless thedouble throw switchl were in strapping position.

Thus 1t can be readily observed that a switch'which' will at once takecare of all three needs of the star delta system of winding is badlyneeded in the art.

In addition to taking care of the star delta winding of a motor. it isamong my objects to provide a sliding contact switch which isself-seating, under control of springs. Thus in my preferred embodiment,the switch bars which are also fuse carriers, are suspended in a movableframe, with springs forcing them downwardly against their contacts.

I further provide a simple and effective mechanism for forcing theoperator of the springs.

Serial No. 349,426.

switch to tirst throw the same to starting position. and from startingto full current position. If released from full-on position. the switchis then automatically returned to neutral by means of a no volt release,which locks the switch on, but if the current is not proper. willrelease the lock by means of its operating solenoid, whereupon it willmove to neutral position, as noted.

As thc switch is under control ot springs and gravity when set upright,as in use, there will be a quick break in each instance from itscontacts, due to the pull of the I therefore provide no special quickbreak mechanism for my switch, although such could be supplied ifnecessary.

The above objects and other advantages which will be noted I accomplishby that certain construction and arrangement of parts to be hereinaftermore specifically pointed out and claimed.

In the drawings,

Figure 1 is a plan view of the switch mechanism with the box coverremoved.

Figure 2 is a side elevation of said operating parts, with the boxcasing broken away.

Figure 3 is an end elevation thereof.

Flgure 4 is a detail, elevation showing the pivoted plate forcontrolling the switch arm as to direction of movement.

Figure 5 is a detail elevation of the balanced lever construction andspring, which act on the switch throwing yoke.

Figure 6 is a perspective of the sequence device.

Figure 7 is a diagram of the switch points and connections for a stardelta motor starting switch.

The switch is preferably mounted in an enclosed box having a base 1,sides 2 and a removable top 3. The box is preferably so made up that theentire switch mechanism and all live contacts are capable of beingvlocked in the box, with sliding covers under control of the switch forpermitting access to the fuses only when the switch is in neutralposition.

In the base of the box, for the star delta switch, are the tive sets ofcontacts A, B, C, D and E, each of which consist of three poles. Asshown in the diagram (Figure 7), the contacts A and C are connectedtogether and to the main line, while poles-I5l and D are connected tothe motor windings M :Ind S respectively. The poles E, however, arel'nerely strapped together.

lVhen l and C are connected, the main line current goes to the molor,and in this position the polesV D and E should he connected so that. themiddle wire is strapped, thereby cutting down the motor current forstarting. nected and poles C and D, the motor is to be in full.operation with oth windings `M and S supplied with current;

Thus it is the object of my switch from this point of v'ew, to havethree b'a'r pesitions, one neutral, a second in position B-C and DE, andathit'd in position A--B and C--D. Furthermore it is the object toforce-the operator to move from nentral to the second position and vfromthesecond to the third i'n rotation, and thence-back" to neutral.

The contacts ar'e -mon'nted in the hase'or bottoni of the box-on anydesired nia-nner` and .comprise flat-,1 levellplats. The movable memberof the switclris a frame of side hars 4f,v 4, ends 5, 5,V and' twocentratbars 6, 6.- This frame slides oni two'tracks 7, 7, located in thebaseof thebox bymeans of depending bars 8 on said-frame. :1

. A \\'ide.yol:e 9 is employed to throw" or slide thefranie, and-engagesinv-apertnrcd plates 10 erected attlie sides' of. theframe in themiddle, thereol.-.?At one sidefof'tlie casing, the yoke i-s merelypivoted in the-"fide wall thereof,- and at-the other itis setin ltheshaft l1, which is-contnolled froxnotitsidcof the casing by a handle 12.vj 'i Extending thmtrglr theend platos 5 land the central cross; platesor bai-s--6,insetsof three,f are springfbelts .13, having helicalsprings 14 around-them. ,These bolts sup- 17, Set therein and arearranged with their port, the switch; barsfll; thereibeirrg one bolt ateach Aend off each `switch .barand three bals side byfside ineaehhali'oItl-reframe..

contacts. as tq accomplish? the-connections A, nect either A andlB,iorBz'and C:

VThe Contact made' by the switch-bals is ensured tobe'an even; 'andcomplete one, due to the springtensien exerted against the hars,whichautomatically forces-them to a perfect seatwancl compensates forany Wear that may take plaeea;

The entire frame is spring-drawn np wardly or toward the contacts A bvjlneans of springs-18,- which. al'ensecined Aat the upper end of theboX.- These springs, in the When poles A and B are :confinainl) as :1.coun(tr-balance 'for the pull of gravity on the sliding tranne, whilethe cin:- trollinsor spring:r is applied to the yoke, as will hedescribed. .i

In its lon'erniost position,` the contacts are arranged to start themotor-` and in the upper position they are arranged to make iheconnections for 1hill runningA strength, while -in central position nocontacts are made, and the switch neutral.

Mounted-in the side of the casing :adjacent the handle in the embodimentshown in the drawings, are two pivoted plates 19, Q0, which areconnected together by a strong spring 21, and bear against the switchaetnati'ng yoke 9. The plate 19 which controls the lower part o theswitch (Fig-nre 5) is stopped hy a pin 22, in a position which willpermit the yoke to be in neutral, or npright position. The plate 2O isalso stopped hy this pin at neutral` and in addition is. stopped in itsdepressed position hy a no volt. release har 23. This har controlled bya solenoid 23, according to usual practice, swings into a position undernormal current, to engage over a: lip 9.4 on the said plate 20. lVhen nocurrent is on, the bar 23 will not engage the plate butin-ill lit` inthe position 23". and there will he .nothing to 'hold the switch in itsnormal running position.

Itwill be noted that the pivot of the har 23 is -snfticient-lyr-offsetfrom the point of engage'nient of the tongue 24er: the plate 20,that-the initial movement the-har is slightly up\'\ar(l.'\vhich willpermitzthc har toswing :u'vay from the plate'QU. Inl -the vdevice soconstructed, .when the switch ha'ndle'is'fmovedgt: th'rbwithe yoke over,toward the "conta-cts Efth'e platel) will hefpressed downbythe yoke,-andpnt the spring 21 under tension.. .The r'elase o'f theoperatingfhandle; by v'the operator will then cause a-n upward rthroiv"vof. theryokeand eontin'ed movement-.of the yoke-will' de.: press theplate 20 (as shown inFtgli-re), therebyputting; the-` spring 21' indertension' in the opposite direction.

Upon release of the switc-lr handle; wheni the switeh is--in its ripperposition, this spring QIQW-ill pull it away from contaetand doivntvneutral position, .being assisted biy gravity i and counterbalaneed bythe springs 18.

The neutral position: is assured by Athe fact that the effect of thisspring -21- isto drawbo'thof the plates 19 and 2() t0 a }'iosi tion incontact with the central stopA pinfl; which is located to assure anupright-posi-A tion of theyoke.`

. To force a proper operation of the handle.; a small boxi25 ism'ountedon t-lrefontside 'o the easing above the shaft/111` and a pin26- on the handle rides in a suitable slo't in thisl constmetion shown'i'n ther-drawings, serve box. Inside of the-box is a balanced .plate 27,spring-held in a central position by means of two springs 28, 28, heldinside the box by suitable screws or otherwise as desired. l

This plate has arcani ridge 29 thereon terminating in a shoulder fromwhich it extends down in* another clam Surface :l0 to a point 31. ',lhepin 26 ou the operating handle rides over this plate :and the camsurfaces thereon. In the position shown iu Figure 4, the switch is inneutral. A downward movement of the handle causes the piu to ride overthe surface 30, and thc spring control of the plate forces the endthereof to a position above the pin. An upward movement of the handlewill then move the pin past the underside of the plate` whereupon theend of the cam ridge will more below the pin, so that upon a return toneutral the pin will have toA ride over the can: ridge.

Once over the cam ridge, the pin rides be hind the shoulder of the camridge, and the handle can no longer be forced hack upwardly because ofthe shoulder engaging the pin. It can be observed that together with thetwo spring plates 19 and 20, the operation of the handle must be in thesuccession several times pointed out above. These must be from neutralto startingr position, from starting position to full running posi tionand from full running position to .neu1 tral7 with the spring platesgiving a quick break. A If it is desired to go back to neutral fromstarting position, a pin 32 may be mounted on the plate 27, whichextends out through the box 25 sutlcientlyV so that when the plate is inits uppermost position, the depression of the pin will throw it-downenough 'to let the handle move back up over the cam end 30. This last isnot necessary and may bc omitted rom'the construction, or some othercorresponding means utilized.

It isbelieved 'that the operation of the switch has beensullicientlydescribed during the courseV of the above specification, and that afurther explanation thereof is not necessary. It is capable of readyobservation that many of the features of the switch described areapplicable to other than star delta switches, and that alternativestructures could well be inserted in place of those described in detailwithout departing from the spirit of my invention, which in itsessential details is a double-throw, double contact switch, having anenforced series o? operations for motor starting, and possessed ofelectrical efficiency and safety for the operator.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent, is:

1. In an electric switch, the combination of a series of five sets ofelectric contacts arranged in line, three contacts in a set, wit-h the.tifth set strapped, and the first :et connected to the line andstrapped to the third sci'. and the second and Jfourth sets connected tothe load by separate wires` and a movable switch element, adapted to heshifted lo connect sets one and two and three and four, or selectivelyto connect sets two and three, und four and fire, and to a neutralnonconnccliug position.

2. In an electric switch, the combination of a series of live sets ofelectric contacts arranged in line, three contacts in a set, with thefifth set strapped, and the irst set connected to the line and strappedto the third set, and the second and fourth sets connected to the loadby separate wires, and a movable switch element, adapted to be shiftedto connect sets one and two and three and four, or selectively toconnect sets two and three, and four and live, and to n neutralnonconnecting position, said movable member comprising two sets ofconnector bars, said connector bars carrying fuses therein. i

El. In an electric switch, the combination of a series of live set-s ofelectric contacts arranged in line, three contacts in a set, with theifth set strapped, and the lirst set connected to the line and st-rappedto the third set` and the second and fourth sets connected to the loadby separate wires, and a movable switch element, adapted to be shiftedto connects sets one and two and three and four, or selectively toconnect sets two and three, and four and live, and to a neutralnonconuecting position, and means for enforcing upon the movable membera sequence of movement from neutral to the one active position, thenceto the other active position, and thence to neutral.

4. A motor starting switch adapted to take a. starting posit-ion, a fullrunning position and a neutral position between the other positions, andmeans for enforcing a xn'ovement thereof so that from neutral positionit can move to starting position only, and from starting position tofull-on position only, and from full-on position to neutral positiononly, and manually operable means adapted to inhibit the action of saidenforc ing means so as to permit -the switch being moved from startingto neutral position without passing through full-on position.

5. In an electrical switch, the combination of a box, flat electricalcontacts in the box, a slidable frame in the box, having ends andcentral cross members, and switch bars mounted on each end and thecentral mem bers. the mounting means for the bals comprising boltsslidahle in the ends and cross members, said bolts connected to the barsand having helical springs thereon tending to press the bars away .fromthe said ends and cross members.

G. A motor starting switch adapted to take a starting position,- :1 fullrunning position and a neutral position between the other positions, andmeans to enforce a movement thereof so that from neutral it can move tostarting position only, and from starting posit-ion to full-on posit-iononly, and from full-on position to neutral position only, and manuallyoperable means to perlnitla return from starting position to "neutraGEORGE B. \VADSWORTH.

